Method for making a branch connection under pressure to a pipe and a screwthreaded branch connection for carrying out said method

ABSTRACT

For achieving a branch connection to a pipe under pressure by means of a screwthreaded connector provided with a sealing device interposed between a radially projecting member on the connector and the pipe, there is produced a fluidtight enclosure having an aperture whose contour is connected in the fluidtight manner to the region of the pipe in which the branch connection is to be made. The sealing device is applied against the pipe before producing the enclosure so that the contour of the aperture of the enclosure is connected to the pipe through the applied sealing device. A hole is thereafter drilled in the pipe and tapped and the connector screwed in the tapped hole from inside the enclosure.

11] 3,870,064 Mar. 11, 1975 United States Patent 1191 Vigneron 3,822,7187/1974 Peterson 137/317 METHOD FOR MAKING A BRANCH CONNECTION UNDERPRESSURE TO A PIPE AND A SCREWTHREADED BRANCH Primary ExaminerMartin P.Schwadron CONNECTION FOR CARRYING OUT SAID Assistant ExaminerDavid R.Matthews METHOD Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, [75]Inventor: Pierre Vigneron, Nancy, France Zmn & Macpeak Assignee:Pont-A-Mousson S. A.,

[57] ABSTRACT For achieving a branch connection to a pipe underPont-A-Mousson, France [22] Flled: 1973 pressure by means of ascrewthreaded connector pro- [21] Appl. No.: 337,501 vided with asealing device interposed between a radially projecting member on theconnector and the pipe, there is produced a fluidtight enclosure havingan ap- [30] Foreign Application Priority Data Mar. 31. 1972 erture whosecontour is connected in the fluidtight manner to the region of the pipein which the branch connection is to be made. The sealing device isapplied against the pipe before producing the enclosure [51] 1323b 41/08Fle 41/04 so that the contour of the aperture of the enclosure is [58]Field of Search 137/315, 15, 317, 318; connected to the pipe through theapplied Sealing 285/189 197; 29/157'l vice. A hole is thereafter drilledin the pipe and tapped and the connector screwed in the tapped hole frominside the enclosure.

[56] References Cited UNITED STATES PATENTS 3,349,792 10/1967 Larkin137/318 8 Claims 5 Drawing Figures PATENTED MRI 1 I975 SHEET 1 Bf 2SHZET 2 OF 2 PATENTED MAR] 1 I975 METHOD'FOR MAKING A BRANCH CONNECTIONUNDER PRESSURE TO A PIPE AND A SCREWTHREADED BRANCH CONNECTION FORCARRYING OUT SAID METHOD The present invention relates to a method formaking a branch connection to a pipe, and in particular a metal pipe,under pressure, by means of a connector of the screwthreaded type thesealing of which is not achieved on the screwthread but by interpositionof a sealing device, constituted, for example, by a sealing element anda support member, between the pipe and a member disposed in radiallyprojecting relation on the connector. This type of branch connector issuitable in particular in the branch connections to pipes having a thinwall in respect of which the number of screwthreads is insufficient toensure a good sea] by merely employing the screwthread. The inventionalso relates to screwthreaded branch connections for carrying out saidmethod.

A method of this type is known in which there is produced a fluidtightenclosure defining an aperture the contour of which is applied aroundthe region of the pipe in which the branch connection is to be made,then, from inside the enclosure 21 tapped hole is formed in the pipe,the sealing device is disposed on the pipe around this hole and theconnector is screwed into this hole through the sealing device until itsflange is tightened against the sealing device. For example, there isemployed for this purpose a machine comprising a fluidtight chamberprovided with a bearing plate having an aperture in front of which maybe brought in succession a drilling and tapping tool and a head forsupporting and applying a connector and a sealing device, said tool andsaid head being disposed inside the box and the machine having a set ofinterchangeable bearing plates the shapes of which are adapted to thedifferent dimensions ofthe pipes. The utilisation of this machine forcarrying out the known method comprises fixing a connector and a sealingdevice on its head, directly applying its bearing plate against thepipe, this plate being chosen in such manner that its aperture iscapable of allowing through the sealing device, drilling and tapping thehole, disposing the sealing device around the tapped hole, and screwingthe connector in the latter by means of the tool and head of the machineand finally detaching the machine from the pipe.

Such a method has the following drawbacks among others I The sealingdevice is mounted after the drilling and tapping so that cuttingsare'trapped between this device and the pipe, which adversely affectsthe perfect sealing of the branch connection.

As the connector and sealing device are positioned from inside the box,this positioning is of very low precision and the branch connection isnot always made exactly in the desired place.

As the box is sealed to the pipe over a relatively large area, thesealing is imperfect and leakages may occur in the course ofthemounting, which is particularly disadvantageous when the branchconnection is made on a gas pipe or conduit.

As the sealing device is mounted from inside the box, its orientationmay be unprecise and its sealing effect imperfect which results inleakages around the branch connection when the latter is finally inposition.

the pipe before the connector is screwed in position,

wherein the sealing device is applied against the pipe around saidregion before producing the enclosure and the enclosure is then producedso that the contour of its aperture is connected to the pipe through theapplied sealing device, the drilling and tapping and the screwing beingthereafter carried out from inside the enclosure.

In the case where a machine of the above-indicated type is employed forthis method, the sealing device is applied against the pipe, a connectoris mounted on the head of the machine, the machine is applied by itshearing plate against said device and the hole is drilled and tapped andthe connector is screwed in position through the sealing device beforefinally detaching the machine.

As the sealing device is mounted before the drilling and tapping, nocuttings can be trapped between this device and the pipe. As the devicemay be placed in position on the pipe in a very precise manner, theposition of the branch-connection is also very precise. The bearingplate of the machine bears on the sealing device in a very small areaand the seal of the machine during mounting is improved. Finally, as thesealing device is mounted before applying the machine, it can beperfectly well oriented so that any subsequent leakage in service isavoided.

Another object of the invention is to provide, for carrying out saidmethod, a branch connection to a pipe under pressure, comprising ascrewthreaded connector and a sealing device comprising, mounted on saidconnector, an elastically yieldable annular sealing element and a rigidannular ring interposed between said sealing element and a radial memberintegral with the connector, wherein the sealing element comprises asleeve portion and an outer flange disposed at one end of the sleeveportion and the ring has internally a cavity which has two shoulders andfreely opens axially through its wider part onto an end face of thering, the radial thickness in the free state of the sleeve portion ofthe sealing element being greater than the width of the annular spacebetween the end of the narrowest shoulder and the facing surface of theconnector and the axial thickness in the free state ofthe flange of thesealing element being greater than the axial dimension of the widershoulder.

Further features and advantages of the invention will be apparent fromthe ensuing description'with reference to the accompanying drawings.

In the drawings FIG. 1 is a half-elevational view and half-axialsectional view of a connector according to the invention for carryingout the method according to the invention;

FIG. 2 is a half-elevational and half-axial sectional view of theconnector shown in FIG. 1 as viewed from the left;

FIG. 3 is a plan view of the bearing member of the connector shown inFIG. 1;

FIG. 4 is an axial sectional view of a sealing element in the free statefor the connector, and

FIG. is a diagrammatic view, with parts cut away, of a machine employedin carrying out the method according to the invention, this machinebeing clamped against the pipe and applying the sealing element tightlyagainst the pipe through the bearing member.

In the embodiment shown in the drawings, a connector R, for example ofbrass and screwthreaded at one ofits ends, is to be connected to athin-walled metal pipe T (for example of ductile iron) at apreviouslychosen point P of the wall of this pipe. This point P isusually situated on the upper generatrix of the pipe or in theneighbourhood thereof and in any case in the upper half of the pipe.

The branch connection to be mounted comprises three parts the connectorR which is tubular and has a screwthreaded end portion and is providedwith an annular flange; the latter is defined adjacent the screwthreadby a plane shoulder perpendicular to its axis; this connector may alsobe of bronze, steel or aluminium or plastics material;

an iron annular saddle or ring S having two perpendicular planes ofsymmetry, an upper plane face perpendicular to its two planes ofsymmetry and an inner cavity defining two steps adapted to house thesealing element mentioned hereinafter;

an annular sealing element G which has an L-shaped cross section (theconcavity of the L facing outwardly) and is moulded from rubber or otherelastomeric material.

The tubular connector R has the shape of a cylindrical tube having anaxis X-X and a screwthreaded end portion 1 and a flange 2 which isdefined adjacent the screwthreaded end portion by a plane shoulder 3perpendicular to the axis X-X. The end portion 1 has an outside diametersmaller than the part 4 ofthe connector which is located between thisend portion and the flange 2 and the main part 4 is connected to theportion 1 by a groove 5, the main part 4 having a strictly cylindricalsurface 6. The flange 2 is defined radially by :1 cylindrical surface 7which has two parallel flat surfaces 7a. If desired, the surface 7 maybe replaced by a polyhedral surface having a hexagon base. The upperpart of the connector located above the flange 2 has a screwthreadedportion 8, which permits screwthreadedly engaging a pipe or a take-offtap, and a tapped portion 9 for fixing a plug.

The iron saddle S is a cast ring having two perpendicular planes ofsymmetry which are moreover those of the sections shown in FIGS. 1 and2. Externally the saddle has a plane upper surface 10 perpendicular toits planes of symmetry and circular and a concave lower surface 11 whichis cylindrical and has a diameter equal to the diameter of the pipe T.The outside diameter of the surface 10 is equal to the diameter of theflange 2 of the connector R. If the surface of this flange werepolyhedral having a hexagon base the outside diameter of the surface 10would be equal to that of thecircle inscribing the hexagon. Two flatsurfaces 13 define the saddle in the direction perpendicular to itslongitudinal plane of symmetry which is parallel to the axis of the pipeT. Its outer surface has a frustoconical portion 12 in the vicinity ofthe surface l0.

Internally, the saddle S has an'axial aperture or cavity 14 whosediameter exceeds the diameter of the cylindrical part 4 of the connectorR. This aperture has along its axis three successive parts. The part themost remote from the pipe -T is defined by a cylindrical surface 15whose diameter is slightly greater than the outside diameter of thecylindrical part 4 of the connector R defined by the surface 6. Thesecond part is defined by a frustoconical surface 16 which is divergentin the direction away from the surface 15 toward the pipe T. the meandiameter of the surface 16 being distinctly greater than the diameter ofthe cylindrical part 4 of the connector R. The chamber thus defined isaxially defined by a shoulder 16a located at a distance I from the pipeT which is greater than the distance 1, between the pipe and the lowerend of the cylindrical part 4 of the connector R. Thus, the surface 6 ofthe connector R and the surface 16 of the saddle S confront one anotherover a height h 1 I, the order of magnitude of which is in theneighbourhood for example of that of the thickness of the connector R inits cylindrical part 4. The third part of the aperture which is thelargest and the nearest to the pipe, is defined, axially, by a verydivergent frustoconical surface 17 which connects this part to thesurface 16 and, radially, by another frustoconical surface 18 whichdiverges in the same way as the surface 16 towards the pipe T and hasroughly the same angle of divergence with a mean diameter larger thanthat of the surface 16.

The sealing element G is an annular moulded member which is moulded flatfrom rubber or elastomeric material having a Shore hardness of, forexample, 58.

The sealing element comprises a sleeve portion and an outer flangedisposed at one end of the sleeve portion. The sleeve portion hasparallel inner and outer surfaces both of which are frustoconical anddiverge toward the flange. In the free state before mounting, theoutside diameter of the flange is roughly equal to the smaller diameterof the surface 18 of the saddle S and the larger diameter of the outerfrustoconical surface of the sleeve portion is very slightly greaterthan the smaller diameter of the surface 16 of the saddle. Also, in thefree state of the sealing element, the inner frustoconical surface 19 ofthe sleeve portion has a minimum diameter d which is distinctly lessthan the diameter of the surface 6 but only very slightly less than thatof the screwthreaded end portion 1 of the connector R and a maximumdiameter D which is slightly greater than the diameter of the surface 6.

In the branch connection, the hooking and sealing functions areseparate. The mechanical hooking is achieved by screwing thescrewthreaded portion 1 of the connector in the tapped hole 20 formed inthe wall of the pipe T. The sealing is achieved by means of the sealingelement G which operates in the manner of a sealing element which iscrushed in its lower part between the surface 17 of the saddle and thesurface 21 of the pipe and in the manner of a sealing element which isradially compressed in its upper part between the surface 16 of thesaddle and the surface 6 of the connector. This second sealing elementoperates in the manner of an automatic seal since the conicity of thesurfaces 16 and 17 ensures that the higher the pressure the highercompression of the seal. Further, the saddle S provided with the sealingelement G is finally positioned at the exact point P at which theconnection must be made. The seal between the pipe and the sadclle isensured by the clamping of the machine employed for mounting the branchconnection under pressure onto the pipe.

As shown in FIG. 5, this machine comprises a cylindrical body 22 whichis closed in its upper part by a fluidtight rotatable barrel 23 and inits lower part by a detachable plate 24 which has an aperture 25. Insidethe body there are disposed a tool holder 26 adapted to re-' ceive thedrill and tap 27 and a branch connection holder 28 adapted to receive aconnector R, the tool holder and the connector holder extending throughthe barrel 23 in such manner as to be capable of being shifted fromoutside the machine. the tool holder 26 being shifted by a ratchetwrench 29 and a lead screw 30. This machine is completed by a chain 21which is fixed to the body 22 and is adapted to be clamped or tightenedaround the pipe T. The machine is applied to the saddle S by putting theplate 24 in contact with the frustoconical surface 12 of the saddle. Asealing element may be interposed between the plate 24 and the saddle Sso as to improve the practical conditions of carrying out the method.

The branch connection described hereinbefore is particularly adapted fora branch connection to a water supply conduit or gas supply conduitunder pressure with the aid of a machine for drilling under pressuresuch as that described hereinbefore. The branch connection is made inthe following manner The machine is prepared in particular by mountingthe drill-tap 27 on the holder 26 and screwing the connector R in theholder 28. The body of the pipe T is ground around the point P at theplace where the joint of the branch connection must be made. The sealingelement G is placed in position in the cavities 16a16 and 17-18 of thesaddle S and the assembly comprising the saddle and sealing element isplaced in the right position for the connection around the point P. Themachine is then applied against the saddle S through the plate 24 whilecentering it on the frustoconical part 12 of the saddle and the machineis clamped in position by means of its chain 21 which is tightenedaround the pipe T until the saddle is in contact with the pipe Tthroughout its periphery by its surface 11. In this way, the sealingelement G is crushed onto the pipe by compression of its lower flange 32between the surface 17 of the saddle S and the surface 21 of the pipe Tso that the seal is finally achieved between the saddle and the pipe.Thus, no leakage to the exterior is possible when drilling and tapping,in particular in the case of a branch connection to a gas conduit.

The drilling and then the tapping is carried out by means of thedrill-tap 27 and the connector R is placed in position on the axis ofthe tapping by means of the barrel 23. This connector R is screwed untilit is completely blocked, this blocking being achieved for exam- I pleat mAdaN or 100 mAN (Newton vector metre) or 200 J/rd (Joules perradian). During this operation, the saddle S is held in position byaction on the flat surfaces 13 while the connector R is rotated by theflat surfaces 70 of its flange 2. This screwing has a double action: onone hand it replaces the tightening effect exerted on the saddle S bythe machine in the region of the surface 12, this action being indeedensured by the connector R by the. fact that the shoulder 3 of theflange 2 bears on the plane upper face 10 of the saddle S; on the otherhand, the introduction of the connector R in the aperture 14 of thesaddle produces, in the region of the confronting surfaces 6 of theconnector R and 16 of the saddle S, the required seal between theconnector'and the saddle by the radial compression of the sleeve portion33 of the sealing element G between these surfaces. The space betweenthe screwthreaded portion 1 of the connector and the base of the sealingelement G and particularly the machined groove 5 on the connector serveto accommodate the flow of material due to the various compressions ofthe sealing element G.

The machine is then removed by releasing its chain 31 and untighteningits connector holder 28, this connector holder being unscrewed, whiletaking care to hold the connector stationary with a spanner engaged withits flat faces 70, so as to avoid untightening and adversely affectingthe various seals. A stop-cock or a temporary plug is then mounted onthe head of the connector R.

The branch connection thus achieved has the following advantages, amongothers It comprises only three parts, namely parts R, S and G.

The seal between the saddle and the pipe is achieved before drilling andtapping the latter. Thus the bearing surface is clean before sealing andthe seal is unaffected by cuttings coming from the drilling and tapping.The slight prior grinding of the body of the pipe in the area chosen forthe branch connection is in fact made for this purpose.

Moreover, in order to ensure that cuttings do not adversely affect theseal between the connector and the saddle in the region of the surfaces19 of the sealing element and 6 of the connector which are to come intocontact with each other, the drilling and tapping are carried out underdry conditions. Thus cuttings do not adhere to the surface 19 of thesealing element G during drilling. They merely, depending on theirweight, drop into the pipe at the moment when the aperture opens intothe pipe or are urged higher into the body 22 of the machine under theeffect of the pressure prevailing in the pipe. Note that the veryenveloping shape of the saddle around the sealing element G in theregion of the cavity 17l8 very effectively protects the sealing elementfrom the action of the ground.

The fact that the mounting is carried out with a permanent view of thesaddle during the entire operation results in very clean and precisework. Further, the seal between the machine and the saddle is verylocalized; other devices on the other hand require between the peripheryof the machine and the pipe a seal which is in fact unreliablethroughout the duration of the operations, which is particularlydisadvantageous when the branch connection is to be made on a gasconduit.

The branch connection described hereinbefore has been found to befluidtight at 15 bars water pressure and trials carried out withcompressed air have reached 4 bars. The branch connection can be madewith metal pipes which are cemented internally, provided that a suitabletool resistant to the cement (carbide tip) is employed for the drillingoperation.

It will be understood that modifications may be made to the describedembodiment without departing from the scope of the invention. Forexample, the flange 2 of the connector R may be replaced by a lock nutscrewed on the connector. Likewise, in order to substitute in themachine the connector holder for the tap holder in alignment with theaperture there may be employed, instead of a barrel, the temporaryinterposition of a closure member, which has the advantage ofmaintaining the initial working axis.

Having now described my invention what I claim as new and desire tosecure by Letters Patent is l. A method for making a branch connectionof a' connector to a pipe under pressure, the connector having a body, ascrewthreaded portion and means defining a member projecting radiallyfrom the body, comprising applying a sealing device to the pipe in aregion of the pipe in which the branch connection is to be made, takingmeans defining a fluidtight enclosure having a portion defining anaperture, applying the periphery of the aperture against the sealingdevice, drilling and tapping a hole in the pipe and thereafter screwingthe screwthreaded portion of the connector in the tapped hole frominside the enclosure until said projecting member bears against thesealing device.

2. A method for making a branch connection of a connector to a pipeunder pressure, the connector having a body, a screwthreaded portion andmeans defining a member projecting radially from the body, comprisingapplying a sealing device to the pipe in a region of the pipe in whichthe branch connection is to be made, taking a machine comprising afluidtight box, a bearing member defining an aperture and combined withthe box, means for bringing in succession a drilling and tapping tooldisposed inside the box and a head for supporting and screwing aconnector disposed inside the box in alignment with the aperture,connecting the connector to the head, applying the bearing memberagainst the sealing device and urging the bearing member in thedirection of the pipe, drilling and, tapping a hole in the pipe by meansof the tool, thereafter screwing the connector in the tapped hole bymeans of the head, and detaching the machine from the pipe.

3. A branch connection to a pipe under pressure, comprising a connectorhaving a body, a screwthreaded portion and means defining a radiallyprojecting member integral with the body, a sealing device comprising anelastically yieldable annular sealing element mounted on the body and arigid annular ring coaxial with the interposed between said sealingelement and said radially projecting member and surrounding the body,the sealing element having a sleeve-portion and an outer flange disposedat one end of the sleeve portion and the ring having an internal cavityhaving a first portion defining afirst shoulder and a larger secondportion defining a second shoulder with the first portion, the ringhaving an annular end face adjoining said second portion, the radialthickness in the free state of the sleeve portion of the sealing elementbeing greater than the width of the annular space between the firstportion of the cavity and the body ofthe connector and the axialthickness in the free state of the flange of the sealing element beinggreater than the axial extent of the second portion of the cavity.

4. A branch connection as claimed in claim 3, wherein the sleeve portionof the sealing element is tubular and frustoconical and divergent in thedirection of the flange.

5. A branch connection as claimed in claim 3, wherein the radiallyprojecting member has a first bearing surface bearing against the ringand the ring as a second axial bearing surface which is radially outsidethe first bearing surface.

6. A branch connection as claimed in claim 3, wherein the ring has aportion axially adjacent the cavity and having an axial dimension whichis less than the axial extent of a portion of the body between thescrewthreaded portion and the radially projecting member.

7. A sealing element for a branch connection made under pressurecomprising a sleeve portion and an outer flange disposed at one end ofthe sleeve portion.

8. A thrust ring for a sealing element for a branch connection madeunder pressure, the ring having an in ternal cavity having a firstportion defining a first shoulder and a larger second portion definingwith the first portion a second shoulder and an annular end faceadjoining said second portion.

1. A method for making a branch connection of a connector to a pipeunder pressure, the connector having a body, a screwthreaded portion andmeans defining a member projecting radially from the body, comprisingapplying a sealing device to the pipe in a region of the pipe in whichthe branch connection is to be made, taking means defining a fluidtightenclosure having a portion defining an aperture, applying the peripheryof the aperture against the sealing device, drilling and tapping a holein the pipe and thereafter screwing the screwthreaded portion of theconnector in the tapped hole from inside the enclosure until saidprojecting member bears against the sealing device.
 1. A method formaking a branch connection of a connector to a pipe under pressure, theconnector having a body, a screwthreaded portion and means defining amember projecting radially from the body, comprising applying a sealingdevice to the pipe in a region of the pipe in which the branchconnection is to be made, taking means defining a fluidtight enclosurehaving a portion defining an aperture, applying the periphery of theaperture against the sealing device, drilling and tapping a hole in thepipe and thereafter screwing the screwthreaded portion of the connectorin the tapped hole from inside the enclosure until said projectingmember bears against the sealing device.
 2. A method for making a branchconnection of a connector to a pipe under pressure, the connector havinga body, a screwthreaded portion and means defining a member projectingradially from the body, comprising applying a sealing device to the pipein a region of the pipe in which the branch connection is to be made,taking a machine comprising a fluidtight box, a bearing member definingan aperture and combined with the box, means for bringing in successiona drilling and tapping tool disposed inside the box and a head forsupporting and screwing a connector disposed inside the box in alignmentwith the aperture, connecting the connector to the head, applying thebearing member against the sealing device and urging the bearing memberin the direction of the pipe, drilling and tapping a hole in the pipe bymeans of the tool, thereafter screwing the connector in the tapped holeby means of the head, and detaching the machine from the pipe.
 3. Abranch connection to a pipe under pressure, comprising a connectorhaving a body, a screwthreaded portion and means defining a radiallyprojecting member integral with the body, a sealing device comprising anelastically yieldable annular sealing element mounted on the body and arigid annular rinG coaxial with the interposed between said sealingelement and said radially projecting member and surrounding the body,the sealing element having a sleeve portion and an outer flange disposedat one end of the sleeve portion and the ring having an internal cavityhaving a first portion defining a first shoulder and a larger secondportion defining a second shoulder with the first portion, the ringhaving an annular end face adjoining said second portion, the radialthickness in the free state of the sleeve portion of the sealing elementbeing greater than the width of the annular space between the firstportion of the cavity and the body of the connector and the axialthickness in the free state of the flange of the sealing element beinggreater than the axial extent of the second portion of the cavity.
 4. Abranch connection as claimed in claim 3, wherein the sleeve portion ofthe sealing element is tubular and frustoconical and divergent in thedirection of the flange.
 5. A branch connection as claimed in claim 3,wherein the radially projecting member has a first bearing surfacebearing against the ring and the ring as a second axial bearing surfacewhich is radially outside the first bearing surface.
 6. A branchconnection as claimed in claim 3, wherein the ring has a portion axiallyadjacent the cavity and having an axial dimension which is less than theaxial extent of a portion of the body between the screwthreaded portionand the radially projecting member.
 7. A sealing element for a branchconnection made under pressure comprising a sleeve portion and an outerflange disposed at one end of the sleeve portion.